Civil engineering works use only concrete, steel and road surfacing coatings ( asphalt or bitumen ).
In Construction Sealants - Part I we have discussed the expansion coefficients and movements of concrete and steel in Buildings.
In civil engineering, some parts of the construction may be quite large, for instance segments of concrete bridges, dams, or even road or airports concrete slabs which may reach 10 meters length.
Therefore the expected movements may be also large.
There are 6 different causes of movements:
* thermal expansion and contraction,
* short term expansion and contraction due to variation of water content in the concrete,
* long term shrinkage of concrete: after pouring, concrete will loose slowly the excess of water which was used for mixing. This is a slow process: total shrinkage in European countries is 2.5 10-4.
20 to 30 % of this occurs during the month following pouring, 70 % after one year, 90 % after 5 years.
* Creep of the concrete: under its own weight concrete will creep very slowly: a very large section of a bridge straight at construction, will become very slightly curved after years,